Inbos suddenly shows only the recent mails

If you are viewing the same account on various folders, then I presume the account is set up as an IMAP mail account. So, All emails are saved on the server and you use various computers to access that same email address/account on the server. If you are only seeing a restricted set of emails then it's possible you have a filter operating on that folder. eg: Quick Filter enabled and eg: 'Show only unread mail' selected Please check - is any icon selected in the Quick Filter and that includes the pin icon if yes then click on it to remove the filter. You say'': I can see all my Emails of years past,'' But you not say whether those emails are in Inbox or other folders. It would be reasonable to presume they are not still in the Inbox, but have been organised into other folders or even put into 'Archives' folders. Is it possible you do not see all the necessary imap folders? In Folder Pane * Right click on the imap mail account name folder and select 'Subscribe' * Click on 'Refresh' * Select all the required folders * click on 'OK' You say : ''mails of about the last four weeks are accessible and probably saved, be it in the default folder or a local one.'' '''A default folder''' for the mail account would be Inbox, Drafts, Templates, Sent, Archives, Spam, Trash All other folders in the imap account would be created by you, but they are still imap folders. '''A local one''' - that implies not in the Imap account but in the 'Local Folders' account. Can you be more specific. It sounds like you are saying the missing emails are not just one folder and not just one account. When posting a question please supply info about the computer etc: What OS are using ? What version of Thunderbird are you using ? Are you talking about an IMAP account or a POP account ? Are missing emails in the IMAP account or the POP account or Local Folders account ? It would also be useful to upload images to help explain situation, eg: one image showing computer A that has emails and one image B showing the computer that is missing emails. Then it's possible to compare the two views.